Manufacturing plant for the dehydrogenation of an unsaturated hydrocarbon

Abstract

A manufacturing plant for carrying out a process for the catalytic dehydrogenation of a first unsaturated hydrocarbon to form a second unsaturated hydrocarbon which has one olefinically unsaturated bond more than the first unsaturated hydrocarbon and otherwise an unchanged carbon skeleton, which process comprises: contacting in a first step a feed comprising the first unsaturated hydrocarbon with a first dehydrogenation catalyst having a temperature parameter T 1 and a selectivity parameter S 1 , and contacting in a second step a reaction product of the first step comprising the first unsaturated hydrocarbon and the second unsaturated hydrocarbon with a second dehydrogenation catalyst having a temperature parameter T 2 and a selectivity parameter S 2 , such that T 1 <T 2 and S 1 <S 2 .

1. A manufacturing plant for carrying out a process for the catalytic dehydrogenation of a first unsaturated hydrocarbon to form a second unsaturated hydrocarbon which has one olefinically unsaturated bond more than the first unsaturated hydrocarbon and otherwise an unchanged carbon skeleton, which plant comprises: a first catalyst bed which is configured to receive a feed comprising the first unsaturated hydrocarbon, and which first catalyst bed comprises a first dehydrogenation catalyst having a temperature parameter T 1 , and a selectivity parameter S 1 , and a second catalyst bed which is configured to receive a reaction product formed in the first catalyst bed comprising the first unsaturated hydrocarbon and the second unsaturated hydrocarbon, and which second catalyst bed comprises a second dehydrogenation catalyst having a temperature parameter T 2  and a selectivity parameter S 2 , such that T 1 <T 2  and S 1 <S 2 , wherein “temperature parameter” means the temperature, in ° C., at which the dehydrogenation catalyst in question provides under defined testing conditions a conversion of the first unsaturated hydrocarbon of 70% mole, and “selectivity parameter” means the selectivity, in % mole, to the second unsaturated hydrocarbon which is then achieved. 
     
     
       2. A manufacturing plant as claimed in  claim 1 , which comprises an apparatus for the flame-less combustion of hydrocarbon configured to heat the reaction product formed in the first catalyst bed. 
     
     
       3. A manufacturing plant as claimed in  claim 1 , wherein T 2 −T 1 , is in the range of from 1 to 50° C. 
     
     
       4. A manufacturing plant as claimed in  claim 1 , wherein S 2 −S 1  is in the range of from 0.1 to 5% mole. 
     
     
       5. A manufacturing plant as claimed in  claim 1 , wherein the dehydrogenation catalysts are selected such that their temperature parameters are in the range of from 550 to 650° C., wherein the temperature parameters are as measured in the dehydrogenation of ethylbenzene to obtain styrene applying a tubular reactor which contains a packed bed of the relevant dehydrogenation catalyst and which is operated with axial flow under the following isothermal testing conditions: absolute pressure 76 kPa, steam to ethylbenzene molar ratio 10, and LHSV 0.65 l/l.h, wherein initially the temperature is kept at 600° until stable operation is reached, and subsequently the temperature is adjusted such as to achieve a conversion of 70% mole. 
     
     
       6. A manufacturing plant as claimed in  claim 1 , wherein the dehydrogenation catalysts are selected such that their selectivity parameters are in the range of from 90 to 99% mole, wherein the selectivity parameters are as measured in the dehydrogenation of ethylbenzene to obtain styrene applying a tubular reactor which contains a packed bed of the relevant dehydrogenation catalyst and which is operated with axial flow under the following isothermal testing conditions: absolute pressure 76 kPa, steam to ethylbenzene molar ratio 10, and LHSV 0.65 l/l.h, wherein initially the temperature is kept at 600° C. until stable operation is reached, and subsequently the temperature is adjusted such as to achieve a conversion of 70% mole. 
     
     
       7. A manufacturing plant as claimed in  claim 1 , wherein the dehydrogenation catalysts are based upon iron oxide. 
     
     
       8. A manufacturing plant as claimed in  claim 6 , wherein the dehydrogenation catalysts, independently, are based in addition upon one or more compounds selected from one or more compounds of a lanthanide, one or more compounds of molybdenum, tungsten, copper or chromium, one or more compounds of an alkali metal, and one or more compounds of an alkaline earth metal. 
     
     
       9. A manufacturing plant as claimed in  claim 7 , wherein the dehydrogenation catalysts, independently, are based in addition upon one or more compounds selected from one or more compounds of cerium, one or more compounds of molybdenum or tungsten, one or more compounds of potassium, and one or more compounds of calcium or magnesium. 
     
     
       10. A manufacturing plant as claimed in  claim 1  further comprising a reaction apparatus for polymerizing the second unsaturated hydrocarbon to form a polymer or copolymer comprising monomer units derived from the second unsaturated hydrocarbon.